An assailant stabbed a policeman, two civilians and was shot dead by police just outside Britain's parliament building in London on Wednesday in what police described as a “terrorist incident”.
Amid confusing scenes, it appeared the incident may have unfolded in several locations, including on the nearby Westminster bridge where eyewitnesses said a car had crashed into pedestrians.
At least 20 people were injured due to the incident.
“Officers - including firearms officers - remain on the scene and we are treating this as a terrorist incident until we know otherwise,” London's Metropolitan Police said in a statement.
The incident took place on the first anniversary of attacks by Islamist militants that killed 32 people in Brussels.
Reuters reporters inside the parliament building heard loud bangs and shortly afterwards saw two people lying on the ground in a courtyard just outside, within the perimeter of the parliamentary estate.
A Reuters photographer said he saw at least a dozen people injured on Westminster Bridge, next to parliament.
His photographs showed people lying on the ground, some of them bleeding heavily and one apparently under a bus.
“I just saw a car go out of control, and just go into pedestrians on the bridge,” a woman who gave her name as Bernadette told Sky News. She was on a tour bus on the bridge at the time.
“As we were going across the bridge, we saw people lying on the floor, they were obviously injured. I saw about 10 people maybe. And then the emergency services started to arrive. (Reuters)